unistd.h File Reference

#include <nlibc.h>
#include <errno.h>
#include <stddef.h>

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Enumerations
enum	{ _SC_CLK_TCK = 2 }
Functions
void *	w_sbrk (ptrdiff_t words)
void *	sbrk (ptrdiff_t inc_bytes)
long	sysconf (int name)

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Enumeration Type Documentation

anonymous enum

NAME sysconf - get configuration information at runtime SYNOPSIS #include <unistd.h> long sysconf(int name); DESCRIPTION POSIX allows an application to test at compile- or run-time whether certain options are supported, or what the value is of certain configurable constants or limits. RETURN VALUE If name is invalid, -1 is returned, and errno is set to EINVAL. Otherwise, the value returned is the value of the system resource and errno is not changed. In the case of options, a positive value is returned if a queried option is available, and -1 if it is not. In the case of limits, -1 means that there is no definite limit. apeNEXT IMPLEMENTATION Only a small set of the POSIX.1/POSIX.2 variables is supported. Enumeration values: _SC_CLK_TCK  The number of clock ticks per second. Definition at line 115 of file unistd.h.

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Function Documentation

void* sbrk (  ptrdiff_t  inc_bytes  )

long sysconf (  int  name  )

void* w_sbrk (  ptrdiff_t  words  )

NAME brk, sbrk - change data segment size SYNOPSIS #include <unistd.h> int brk(void *end_data_segment); void *sbrk(ptrdiff_t increment_bytes); void *w_sbrk(ptrdiff_t increment_word); DESCRIPTION brk sets the end of the data segment to the value specified by end_data_segment, when that value is reasonable, the system does have enough memory and the process does not exceed its max data size (see setrlimit(2)). sbrk increments the program's data space by increment bytes. sbrk isn't a system call, it is just a C library wrapper. Calling sbrk with an increment of 0 can be used to find the current location of the program break. w_sbrk is a variant of sbrk that accepts the increment in words. RETURN VALUE On success, brk returns zero, and sbrk returns a pointer to the start of the new area. On error, -1 is returned, and errno is set to ENOMEM. apeNEXT IMPLEMENTATION Memory is allocated in units of words. On error an exception is thrown.

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