C Standard Library Functions


This is a list of function prototypes in the standard C library in alphabetical order and a list of prototypes grouped by functionality.
Description:
The Comments column contains a very brief description of the use of the function. The list is not complete, however it provides information on the major functions in the C Runtime Library. It should, at the very least, indicate what functions are available in the standard C library allow you to do more investigation on your own. Some of the C library functions documented elsewhere may not be available in FreeBASIC. Check the appropriate include file for more information.

Note: The following prototypes are not the official FreeBASIC prototypes (see the include files), however, they will give you enough information to properly use the functions.

The Include File column contains the name of the file which you must include, using the #include directive at the beginning of your program. If you don't include the appropriate include file, the program either will not compile, or it will compile apparently correctly but give incorrect results when run. All of the C Runtime headers are located in the crt directory; for example, if the specified header is math.bi, use #include "crt/math.bi" or #include "crt\math.bi", our just #include "crt.bi" including all the others.

The Prototype column contains the following information:
  • The name of the function;
  • The parameters required for the function in parenthesis, together with the data-type of the parameters;
  • The data-type of the value returned by the function.

For example atoi(a as zstring ptr) as integer means that the function atoi returns a value of type integer and requires a character zstring ptr as its argument.

Note: In order to make calling the C runtime functions very easy, any string type argument may be directly passed to a procedure referring to a parameter declared as 'zstring ptr'. The compiler performs itself an automatic conversion (without warning message) between string and 'zstring ptr'.

Alphabetical List
Name Prototype (with parameters) Include File Comments
abs_ abs_(n as integer) as integer stdlib.bi Returns the absolute value (i.e. positive value)
acos_ acos_(a as double) as double math.bi Returns the inverse cosine (angle in radians)
asin_ asin_(a as double) as double math.bi Returns the inverse sine (angle in radians)
atan_ atan_(a as double) as double math.bi Returns the inverse tan (angle in radians)
atan2_ atan2_(y as double, x as double) as double math.bi Returns the inverse tan (pass the opposite as y and the adjacent as x)
atoi atoi(s as zstring ptr) as integer stdlib.bi Converts a character zstring of digits to a number of type integer.
atof atof(s as zstring ptr) as double stdlib.bi Converts a character zstring of digits to a number of type double.
calloc calloc(NumElts as integer, EltSiz as integer) as any ptr stdlib.bi Allocates memory. Returns a pointer to a buffer for an array having NumElts elements, each of size EltSiz bytes.
ceil ceil(d as double) as double math.bi Returns the nearest whole number above the value passed.
clearerr clearerr(s as FILE ptr) stdio.bi Clears the error indicators on a file stream (read or write).
cos_ cos_(ar as double) as double math.bi Returns the cosine of an angle measured in radians.
cosh cosh(x as double) as double math.bi Returns the hyperbolic cosine of an angle measured in radians.
div div(num as integer, denom as integer) as div_t stdlib.bi Returns the quotient and remainder of a division as a structure of type div_t.
ecvt ecvt(x as double) as zstring ptr math.bi Converts a number to a zstring.
exit_ exit_(status as integer) stdlib.bi Exits a program. It will flush file buffers and closes all opened files, and run any functions called by atexit().
exp_ exp_(a as double) as double math.bi Returns the value of e raised to the power of the argument (Inverse to natural logarithm).
fabs fabs(d as double) as double math.bi Returns the absolute value (i.e. positive value) of type double.
fclose fclose(s as FILE ptr) as FILE ptr stdio.bi Closes a file. Returns 0 if successful otherwise EOF.
feof feof(s as FILE ptr) as integer stdio.bi Returns value of end-of-file indicator . (0 if not eof). Indicator will clear itself but can be reset by clearerr().
ferror ferror(s as FILE ptr) as integer stdio.bi Returns error indicator for a stream (0 if no error). Error indicator is reset by clearerr() or rewind().
fflush fflush(s as FILE ptr) as integer stdio.bi Flushes (i.e. deletes) a stream (use stdin to flush the stream from the keyboard). Returns 0 if successful.
fgetc fgetc(s as FILE ptr) as integer stdio.bi Single character input (in ASCII) from passed stream (stdin for keyboard).
fgetpos fgetpos(s as FILE ptr, c as fpos_t ptr) as integer stdio.bi Saves the position of the file pointer on stream s at the location pointed to by c.
fgets fgets(b as zstring ptr, n as integer, s as FILE ptr) as zstring ptr stdio.bi From the stream s reads up to n-1 characters to buffer b.
floor floor(d as double) as double math.bi Returns the nearest whole number below the value passed.
fmod fmod(x as double, y as double) as double math.bi Calculates the remainder of x divided by y.
fopen fopen(file as zstring ptr, mode as zstring ptr) as FILE ptr stdio.bi Opens a file. Pass the DOS name of the file and a code to indicate whether for reading, writing, or appending. Codes are r for read, w for write, + for read and write, a for append and b to indicate binary.
fprintf fprintf(s as FILE ptr, fmt as zstring ptr, ...) as integer stdio.bi Prints on stream s as many items as there are single % signs in fmt that have matching arguments in the list.
fputc fputc(c as integer, s as FILE ptr) as integer stdio.bi Outputs the single character c to the stream s.
fputs fputs(b as zstring ptr, s as FILE ptr) as integer stdio.bi Sends the character stream in b to stream s, returns 0 if the operation fails.
fread fread(buf as any ptr, b as size_t, c as size_t, s as FILE ptr) as integer stdio.bi Reads the number c items of data of size b bytes from file s to the buffer buf. Returns the number of data items actually read.
free free(p as any ptr) stdlib.bi Frees the memory allocation for a pointer p to enable this memory to be used.
freopen freopen(file as zstring ptr, mode as zstring ptr, s as FILE ptr) as FILE ptr stdio.bi Opens a file for redirecting a stream. e.g. freopen("myfile", "w", stdout) will redirect the standard output to the opened "myfile".
frexp frexp(x as double, p as integer ptr) as double math.bi Calculates a value m so that x equals m times 2 to some power. p is a pointer to m.
fscanf fscanf(s as FILE ptr, fmt as zstring ptr, ...) as integer stdio.bi Reads from stream s as many items as there are % signs in fmt with corresponding listed pointers.
fseek fseek(s as FILE ptr, offset as integer, origin as integer) as integer stdio.bi Locates a file pointer. With origin 0, 1 or 2 for the beginning, offset bytes into and at the end of the stream.
fsetpos fsetpos(s as FILE ptr, p as fpos_t ptr) as integer stdio.bi Sets the file pointer for the stream s to the value pointed to by p.
ftell ftell(s as FILE ptr) as long stdio.bi Locates the position of the file pointer for the stream s.
fwrite fwrite(buf as any ptr, b as integer, c as integer, s as FILE ptr) as integer stdio.bi Writes the number c items of data of size b bytes from the buffer buf to the file s. Returns the number of data items actually written.
getc getc(s as FILE ptr) as integer stdio.bi Macro for single character input (in ASCII) from passed stream. (stdin for keyboard)
getchar getchar() as integer stdio.bi Single character input from the standard input
gets gets(b as zstring ptr) as zstring ptr stdio.bi Reads a stream of characters from the standard input until it meets \n or EOF.
hypot hypot(x as double, y as double) as double math.bi Calculates the hypotenuse from the sides x and y.
isalnum isalnum(c as integer) as integer ctype.bi Returns a non zero value if character c is alphabetic or a digit.
isalpha isalpha(c as integer) as integer ctype.bi Returns a non zero value if character c is alphabetic.
iscntrl iscntrl(c as integer) as integer ctype.bi Returns a non zero value if character c is a control character.
isdigit isdigit(c as integer) as integer ctype.bi Returns a non zero value if character c is a digit.
isgraph isgraph(c as integer) as integer ctype.bi Returns a non zero value if character c is alphabetic.
islower islower(c as integer) as integer ctype.bi Returns a non-zero value if character c is a lower case character.
isprint isprint(c as integer) as integer ctype.bi Returns a non zero value if character c is printable.
ispunct ispunct(c as integer) as integer ctype.bi Returns a non zero value if character c is a punctuation character.
isspace isspace(c as integer) as integer ctype.bi Returns a non zero value if character c denotes a space.
isupper isupper(c as integer) as integer ctype.bi Returns a non-zero value if character c is an upper case character.
isxdigit isxdigit(c as integer) as integer ctype.bi Returns a non-zero value if character c is a hex digit (0 to F or f).
ldexp ldexp(x as double, n as integer) as double math.bi Returns the product of x and 2 to the power n.
ldiv ldiv(num as long, denom as long) as ldiv_t stdlib.bi Returns the quotient and remainder of a division as a structure of type ldiv_t.
log_ log_(a as double) as double math.bi Returns the natural logarithm of the argument.
log10 log10(a as double) as double math.bi Returns the logarithm to the base 10 of the argument.
malloc malloc(bytes as integer) as any ptr stdlib.bi Allocates memory. Returns a pointer to a buffer comprising storage for the specified size.
modf modf(d as double, p as double ptr) as double math.bi Returns the fractional part of a floating point number d. p points to the integral part expressed as a float.
perror perror(mess as zstring ptr) stdio.bi Prints on the stream stderr a message passed as the argument.
pow pow(x as double, y as double) as double math.bi Returns x to the power y.
pow10 pow10(x as double) as double math.bi Returns 10 to the power x (inverse function to log10()).
printf printf(fmt as zstring ptr, ...) as integer stdio.bi Prints on standard output as many items as there are single % signs in fmt with matching arguments in the list.
putc putc(c as integer, s as FILE ptr) as integer stdio.bi Macro to output the single character c to the stream s.
putchar putchar(c as integer) as integer stdio.bi Macro to output the single character c to the standard output.
puts puts(b as zstring ptr) as integer stdio.bi Sends the character stream in b to the standard output, returns 0 if operation fails.
rand rand() as integer stdlib.bi Returns a pseudo random number. A seed is required. The seed is set with srand.
realloc realloc(p as any ptr, newsize as size_t) as any ptr stdlib.bi Allocates memory. Returns a pointer to a buffer for a change in size of object pointed to by p.
rewind rewind(s as FILE ptr) stdio.bi Clears the error indicators on a file stream (read or write). Necessary before reading an amended file.
scanf scanf(fmt as zstring ptr, ...) as integer stdio.bi Reads from standard input as many items as there are % signs in fmt with corresponding listed pointers.
sin_ sin_(ar as double) as double math.bi Returns the sine of an angle measured in radians.
sinh sinh(x as double) as double math.bi Returns the hyperbolic sine of an angle measured in radians.
sprintf sprintf(p as zstring ptr, fmt as zstring ptr, ...) as integer stdio.bi Prints on zstring p as many items as there are single % signs in fmt that have matching arguments in the list.
sqrt sqrt(a as double) as double math.bi Returns the square root of the value passed. Domain error if value is negative.
srand srand(seed as uinteger) stdlib.bi Sets the seed for a random number. A possible seed is the current time.
sscanf sscanf(b as zstring ptr, fmt as zstring ptr, ...) as integer stdio.bi Reads from buffer b as many items as there are % signs in fmt with corresponding listed pointers.
strcat strcat(s1 as zstring ptr, s2 as zstring ptr) as zstring ptr string.bi Concatenates (appends) zstring s2 to s1.
strchr strchr(s as zstring ptr, c as integer) as zstring ptr string.bi Returns a pointer to the first occurrence of c in s or NULL if it fails to find one.
strcmp strcmp(s1 as zstring ptr, s2 as zstring ptr) as integer string.bi Compares zstring s2 to s1. Returns 0 or signed difference in ASCII values of first non matching character.
strcpy strcpy(s1 as zstring ptr, s2 as zstring ptr) as zstring ptr string.bi Copies s2 into s1.
strcspn strcspn(s1 as zstring ptr, s2 as zstring ptr) as integer string.bi Returns the number of characters in s1 encountered before meeting any of the characters in s2.
strerror strerror(n as integer) as zstring ptr string.bi Returns a pointer to a system error message corresponding to the passed error number.
strlen strlen(s as zstring ptr) as integer string.bi Returns the number of bytes in the null terminated zstring pointed to by s (does not count null).
strncat strncat(s1 as zstring ptr, s2 as zstring ptr, n as integer) as zstring ptr string.bi Concatenates (appends) n bytes from zstring s2 to s1.
strncmp strncmp(s1 as zstring ptr, s2 as any ptr, n as integer) as integer string.bi Compares n bytes of zstring s2 to the same of s1. Returns 0 or signed difference in ASCII values of first non matching character.
strncpy strncpy(s1 as zstring ptr, s2 as zstring ptr, n as integer) as zstring ptr string.bi Copies n bytes from s2 into s1.
strpbrk strpbrk(s1 as zstring ptr, s2 as zstring ptr) as zstring ptr string.bi Returns a pointer to the first character encountered in s1 that is also in s2.
strrchr strrchr(s as zstring ptr, c as integer) as zstring ptr string.bi Returns a pointer to the last occurrence of c in s or NULL if it fails to find one.
strspn strspn(s1 as zstring ptr, s2 as zstring ptr) as integer string.bi Returns the number of characters in s1 encountered before meeting a character which is not in s2.
strstr strstr(s1 as zstring ptr, s2 as zstring ptr) as zstring ptr string.bi Finds the location of the zstring s2 in s1 and returns a pointer to its leading character.
strtod strtod(s as zstring ptr, p as zstring ptr) as double stdlib.bi Converts a zstring to double, provided the zstring is written in the form of a number.
strtok strtok(s1 as zstring ptr, s2 as zstring ptr) as zstring ptr string.bi Returns pointers to successive tokens utilizing the zstring s1. Tokens regarded as separators are listed in s2.
system system(command as zstring ptr) as integer stdlib.bi Executes, from within a program, a command addressed to the operating system written as a zstring (e.g. DIR on Windows and DOS and LS on Linux).
tan_ tan_(ar as double) as double math.bi Returns the tangent of an angle measured in radians.
tanh tanh(x as double) as double math.bi Returns the hyperbolic tangent of an angle measured in radians.
tolower tolower(c as integer) as integer ctype.bi Converts a character from upper case to lower case (uses ASCII code).
toupper toupper(c as integer) as integer ctype.bi Converts a character from lower case to upper case (uses ASCII code).
ungetc ungetc(c as integer, s as FILE ptr) as integer stdio.bi Pushes a character c back into the stream s, returns EOF if unsuccessful. Do not push more than one character.


Buffer Manipulation
#include "crt/string.bi"
Prototype (with parameters) Comments
memchr(s as any ptr, c as integer, n as size_t) as any ptr Search for a character in a buffer.
memcmp(s1 as any ptr, s2 as any ptr, n as size_t) as integer Compare two buffers.
memcpy(dest as any ptr, src as any ptr, n as size_t) as any ptr Copy one buffer into another .
memmove(dest as any ptr, src as any ptr, n as size_t) as any ptr Move a number of bytes from one buffer lo another.
memset(s as any ptr, c as integer, n as size_t) as any ptr Set all bytes of a buffer to a given character.


Character Classification and Conversion
#include "crt/ctype.bi"
Prototype (with parameters) Comments
isalnum(c as integer) as integer True if c is alphanumeric.
isalpha(c as integer) as integer True if c is a letter.
isascii(c as integer) as integer True if c is ASCII .
iscntrl(c as integer) as integer True if c is a control character.
isdigit(c as integer) as integer True if c is a decimal digit.
isgraph(c as integer) as integer True if c is a graphical character.
islower(c as integer) as integer True if c is a lowercase letter.
isprint(c as integer) as integer True if c is a printable character.
ispunct(c as integer) as integer True if c is a punctuation character.
isspace(c as integer) as integer True if c is a space character.
isupper(c as integer) as integer True if c is an uppercase letter.
isxdigit(c as integer) as integer True if c is a hexadecimal digit.
toascii(c as integer) as integer Convert c to ASCII .
tolower(c as integer) as integer Convert c to lowercase.
toupper(c as integer) as integer Convert c to uppercase.


Data Conversion
#include "crt/stdlib.bi"
Prototype (with parameters) Comments
atof(string1 as zstring ptr) as double Convert zstring to floating point value.
atoi(string1 as zstring ptr) as integer Convert zstring to an integer value.
atol(string1 as zstring ptr) as integer Convert zstring to a long integer value.
itoa(value as integer, zstring as zstring ptr, radix as integer) as zstring ptr Convert an integer value to a zstring using given radix.
ltoa(value as long, zstring as zstring ptr, radix as integer) as zstring ptr Convert long integer to zstring in a given radix.
strtod(string1 as zstring ptr, endptr as zstring ptr) as double Convert zstring to a floating point value.
strtol(string1 as zstring ptr, endptr as zstring ptr, radix as integer) as long Convert zstring to a long integer using a given radix.
strtoul(string1 as zstring ptr, endptr as zstring ptr, radix as integer) as ulong Convert zstring to unsigned long.


Directory Manipulation
#include "crt/io.bi"
Prototype (with parameters) Comments
_chdir(path as zstring ptr) as integer Change current directory to given path.
_getcwd(path as zstring ptr, numchars as integer) as zstring ptr Returns name of current working directory.
_mkdir(path as zstring ptr) as integer Create a directory using given path name.
_rmdir(path as zstring ptr) as integer Delete a specified directory.


File Manipulation
#include "crt/sys/stat.bi"
#include "crt/io.bi"
Prototype (with parameters) Comments
chmod(path as zstring ptr, pmode as integer) as integer Change permission settings of a file.
fstat(handle as integer, buffer as type stat ptr) as integer Get file status information.
remove(path as zstring ptr) as integer Delete a named file.
rename_(oldname as zstring ptr, newname as zstring ptr) as integer rename a file.
stat(path as zstring ptr, buffer as type stat ptr) as integer Get file status information of named file.
umask(pmode as uinteger) as uinteger Set file permission mask.


Stream I/O
#include "crt/stdio.bi"
Prototype (with parameters) Comments
clearerr(file_pointer as FILE ptr) Clear error indicator of stream,
fclose(file_pointer as FILE ptr) as integer Close a file,
feof(file_pointer as FILE ptr) as integer Check if end of file occurred on a stream.
ferror(file_pointer as FILE ptr) as integer Check if any error occurred during file I/0.
fflush(file_pointer as FILE ptr) as integer Write out (flush) buffer to file.
fgetc(file_pointer as FILE ptr) as integer Get a character from a stream.
fgetpos(file_pointer as FILE ptr, fpos_t current_pos) as integer Get the current position in a stream.
fgets(string1 as zstring ptr, maxchar as integer, file_pointer as FILE ptr) as zstring ptr Read a zstring from a file.
fopen(filename as zstring ptr, access_mode as zstring ptr) as FILE ptr Open a file for buffered I/0.
fprintf(file_pointer as FILE ptr, format_string as zstring ptr, args) as integer Write formatted output to a file,
fputc(c as integer, file_pointer as FILE ptr) as integer Write a character to a stream.
fputchar(c as integer) as integer Write a character to stdout.
fputs(string1 as zstring ptr, file_pointer as FILE ptr) as integer Write a zstring to a stream.
fread(buffer as zstring ptr, size as size_t count as size_t, file_pointer as FILE ptr) as size_t Read unformatted data from a stream into a buffer.
freopen(filename as zstring ptr, access as zstring ptr mode, file_pointer as FILE ptr) as FILE ptr Reassign a file pointer to a different file.
fscanf(file_pointer as FILE ptr, format as zstring ptr zstring, args) as integer Read formatted input from a stream.
fseek(file_pointer as FILE ptr, offset as long, origin as integer) as integer Set current position in file to a new location.
fsetpos(file_pointer as FILE ptr, current_pos as fpos_t) as integer Set current position in file to a new location.
ftell(file_pointer as FILE ptr) as long Get current location in file.
fwrite(buffer as zstring ptr, size as size_t, count as size_t file_pointer as FILE ptr) as size_t Write unformatted data from a buffer to a stream.
getc(file_pointer as FILE ptr) as integer Read a character from a stream.
getchar() as integer Read a character from stdin.
gets(buffer as zstring ptr) as zstring ptr Read a line from stdin into a buffer.
printf(format as zstring ptr _string, args) as integer Write formatted output to stdout.
putc(c as integer, file_pointer as FILE ptr) as integer Write a character to a stream.
putchar(c as integer) as integer Write a character to stdout.
puts(string1 as zstring ptr) as integer Write a zstring to stdout.
rewind(file_pointer as FILE ptr) Rewind a file.
scanf(format_string as zstring ptr, args) as integer Read formatted input from stdin.
setbuf(file_pointer as FILE ptr, buffer as zstring ptr) Set up a new buffer for the stream.
setvbuf(file_pointer as FILE ptr, buffer as zstring ptr, buf_type as integer, buf as size_t size) as integer Set up new buffer and control the level of buffering on a stream.
sprintf(string1 as zstring ptr, format_string as zstring ptr, args) as integer Write formatted output to a zstring.
sscanf(buffer as zstring ptr, format_string as zstring ptr, args) as integer Read formatted input from a zstring.
tmpfile() as FILE ptr Open a temporary file.
tmpnam(file_name as zstring ptr) as zstring ptr Get temporary file name.
ungetc(c as integer, file_pointer as FILE ptr) as integer Push back character into stream' s buffer


Low level I/O
#include "crt/io.bi"
So far Win32 only, connects to MSVCRT.DLL (headers missing for other platforms)
Prototype (with parameters) Comments
_close(handle as integer) as integer Close a file opened for unbuffered I/O.
_creat(filename as zstring ptr, pmode as integer) as integer Create a new file with specified permission setting.
_eof(handle as integer) as integer Check for end of file.
_lseek(handle as integer, offset as long, origin as integer) as long Go to a specific position in a file.
_open(filename as zstring ptr, oflag as integer, pmode as uinteger) as integer Open a file for low-level I/O.
_read(handle as integer, buffer as zstring ptr, length as uinteger) as integer Read binary data from a file into a buffer.
_write(handle as integer, buffer as zstring ptr, count as uinteger) as integer Write binary data from a buffer to a file.


Mathematics
#include "crt/math.bi"
Prototype (with parameters) Comments
abs_(n as integer) as integer Get absolute value of an integer.
acos_(x as double) as double Compute arc cosine of x.
asin_(x as double) as double Compute arc sine of x.
atan_(x as double) as double Compute arc tangent of x.
atan2_(y as double, x as double) as double Compute arc tangent of y/x.
ceil(x as double) as double Get smallest integral value that exceeds x.
cos_(x as double) as double Compute cosine of angle in radians.
cosh(x as double) as double Compute the hyperbolic cosine of x.
div(number as integer, denom as integer) as div_t Divide one integer by another.
exp_(x as double) as double Compute exponential of x.
fabs(x as double) as double Compute absolute value of x.
floor(x as double) as double Get largest integral value less than x.
fmod(x as double, y as double) as double Divide x by y with integral quotient and return remainder.
frexp(x as double, expptr as integer ptr) as double Breaks down x into mantissa and exponent of no.
labs(n as long) as long Find absolute value of long integer n.
ldexp(x as double, exp as integer) as double Reconstructs x out of mantissa and exponent of two.
ldiv(number as long, denom as long) as ldiv_t Divide one long integer by another.
log_(x as double) as double Compute log(x).
log10(x as double) as double Compute log to the base 10 of x.
modf(x as double, intptr as double ptr) as double Breaks x into fractional and integer parts.
pow(x as double, y as double) as double Compute x raised to the power y.
rand() as integer Get a random integer between 0 and 32767.
random(max_num as integer) as integer Get a random integer between 0 and max_num.
randomize() Set a random seed for the random number generator.
sin_(x as double) as double Compute sine of angle in radians.
sinh(x as double) as double Compute the hyperbolic sine of x.
sqrt(x as double) as double Compute the square root of x.
srand(seed as uinteger) Set a new seed for the random number generator (rand).
tan_(x as double) as double Compute tangent of angle in radians.
tanh(x as double) as double Compute the hyperbolic tangent of x.


Memory Allocation
#include "crt/stdlib.bi"
Prototype (with parameters) Comments
calloc(num as size_t elems, elem_size as size_t) as any ptr Allocate an array and initialise all elements to zero .
free(mem_address as any ptr) Free a block of memory.
malloc(num as size_t bytes) as any ptr Allocate a block of memory.
realloc(mem_address as any ptr, newsize as size_t) as any ptr Reallocate (adjust size) a block of memory.


Process Control
#include "crt/stdlib.bi"
Prototype (with parameters) Comments
abort() Abort a process.
execl(path as zstring ptr, arg0 as zstring ptr, arg1 as zstring ptr,..., NULL) as integer Launch a child process (pass command line).
execlp(path as zstring ptr, arg0 as zstring ptr, arg1 as zstring ptr,..., NULL) as integer Launch child (use PATH, pass command line).
execv(path as zstring ptr, argv as zstring ptr) as integer Launch child (pass argument vector).
execvp(path as zstring ptr, argv as zstring ptr) as integer Launch child (use PATH, pass argument vector).
exit_(status as integer) Terminate process after flushing all buffers.
getenv(varname as zstring ptr) as zstring ptr Get definition of environment variable,
perror(string1 as zstring ptr) Print error message corresponding to last system error.
putenv(envstring as zstring ptr) as integer Insert new definition into environment table.
raise(signum as integer) as integer Generate a C signal (exception).
system_(string1 as zstring ptr) as integer Execute a resident operating system command.


Searching and Sorting
#include "crt/stdlib.bi"
Note: The compare callback function required by bsearch and qsort must be declared as cdecl. It must return a value <0 if its first argument should be located before the second one in the sorted array, >0 if the first argument should be located after the second one, and zero if their relative positions are indifferent (equal values).

Prototype (with parameters) Comments
bsearch(key as any ptr, base as any ptr, num as size_t, width as size_t, compare as function(elem1 as any ptr, elem2 as any ptr) as integer) as any ptr Perform binary search.
qsort(base as any ptr, num as size_t, width as size_t, compare as function(elem1 as any ptr, elem2 as any ptr) as integer) Use the quicksort algorithm to sort an array.


String Manipulation
#include "crt/string.bi"
Prototype (with parameters) Comments
stpcpy(dest as zstring ptr, src as zstring ptr) as zstring ptr Copy one zstring into another.
strcmp(string1 as zstring ptr, string2 as zstring ptr) as integer Compare string1 and string2 to determine alphabetic order.
strcpy(string1 as zstring ptr, string2 as zstring ptr) as zstring ptr Copy string2 to string1.
strerror(errnum as integer) as zstring ptr Get error message corresponding to specified error number.
strlen(string1 as zstring ptr) as integer Determine the length of a zstring.
strncat(string1 as zstring ptr, string2 as zstring ptr, n as size_t) as zstring ptr Append n characters from string2 to string1.
strncmp(string1 as zstring ptr, string2 as zstring ptr, n as size_t) as integer Compare first n characters of two strings.
strncpy(string1 as zstring ptr, string2 as zstring ptr, n as size_t) as zstring ptr Copy first n characters of string2 to string1.
strnset(string1 as zstring ptr, c as integer, size _t n) as zstring ptr Set first n characters of zstring to c.
strrchr(string1 as zstring ptr, c as integer) as zstring ptr Find last occurrence of character c in zstring.


Time
#include "crt/time.bi"
Prototype (with parameters) Comments
asctime(time as type tm ptr) as zstring ptr Convert time from type tm to zstring.
clock() as clock_t Get elapsed processor time in clock ticks.
ctime(time as time_t ptr) as zstring ptr Convert binary time to zstring.
difftime(time_t time2, time_t time1) as double Compute the difference between two times in seconds.
gmtime(time as time_t ptr) as type tm ptr Get Greenwich Mean Time (GMT) in a tm structure.
localtime(time as time_t ptr) as type tm ptr Get the local time in a tm structure.
time_(timeptr as time_t ptr) as time_t Get current time as seconds elapsed since 0 hours GMT 1/1/70.


See also:
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