table of contents
|PROFIL(2)||System Calls Manual||PROFIL(2)|
NAME¶profil — control process profiling
LIBRARY¶Standard C Library (libc, -lc)
SYNOPSIS¶#include <unistd.h> int
profil(char *samples, size_t size, vm_offset_t offset, int scale);
DESCRIPTION¶The profil() system call enables or disables program counter profiling of the current process. If profiling is enabled, then at every profiling clock tick, the kernel updates an appropriate count in the samples buffer. The frequency of the profiling clock is recorded in the header in the profiling output file. The buffer samples contains size bytes and is divided into a series of 16-bit bins. Each bin counts the number of times the program counter was in a particular address range in the process when a profiling clock tick occurred while profiling was enabled. For a given program counter address, the number of the corresponding bin is given by the relation:
[(pc - offset) / 2] * scale / 65536
RETURN VALUES¶The profil() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.
- profiling C run-time startup file
- conventional name for profiling output file
ERRORS¶The following error may be reported:
- The buffer samples contains an invalid address.
HISTORY¶The profil() function appeared in Version 7 AT&T UNIX.
BUGS¶This routine should be named profile(). The samples argument should really be a vector of type unsigned short. The format of the gmon.out file is undocumented.
|June 4, 1993||Debian|