intro - introduction to library functions
Section 3 of the manual describes all library functions excluding the
library functions (system call wrappers) described in Section 2, which
implement system calls.
Many of the functions described in the section are part of the Standard
C Library (libc). Some functions are part of other libraries (e.g.,
the math library, libm, or the real-time library, librt) in which case
the manual page will indicate the linker option needed to link against
the required library (e.g., -lm and -lrt, respectively, for the
In some cases, the programmer must define a feature test macro in order
to obtain the declaration of a function from the header file specified
in the man page SYNOPSIS section. (Where required, these feature test
macros must be defined before including any header files.) In such
cases, the required macro is described in the man page. For further
information on feature test macros, see feature_test_macros(7).
Certain terms and abbreviations are used to indicate UNIX variants and
standards to which calls in this section conform. See standards(7).
Authors and copyright conditions
Look at the header of the manual page source for the author(s) and
copyright conditions. Note that these can be different from page to
intro(2), errno(3), capabilities(7), credentials(7), environ(7),
feature_test_macros(7), libc(7), math_error(7), path_resolution(7),
pthreads(7), signal(7), standards(7)
This page is part of release 3.65 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.