intro(3) Library Functions Manual intro(3)
NAME
intro - introduction to library functions
DESCRIPTION
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 afore-
mentioned libraries).
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).
Subsections
Section 3 of this manual is organized into subsections that reflect the
complex structure of the standard C library and its many implementa-
tions:
• 3const
• 3head
• 3type
This difficult history frequently makes it a poor example to follow in
design, implementation, and presentation.
Ideally, a library for the C language is designed such that each header
file presents the interface to a coherent software module. It provides
a small number of function declarations and exposes only data types and
constants that are required for use of those functions. Together,
these are termed an API or application program interface. Types and
constants to be shared among multiple APIs should be placed in header
files that declare no functions. This organization permits a C library
module to be documented concisely with one header file per manual page.
Such an approach improves the readability and accessibility of library
documentation, and thereby the usability of the software.
STANDARDS
Certain terms and abbreviations are used to indicate UNIX variants and
standards to which calls in this section conform. See standards(7).
NOTES
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
page!
SEE ALSO
intro(2), errno(3), capabilities(7), credentials(7), environ(7), fea-
ture_test_macros(7), libc(7), math_error(7), path_resolution(7),
pthreads(7), signal(7), standards(7), system_data_types(7)
Linux man-pages 6.03 2023-02-05 intro(3)
Generated by dwww version 1.15 on Sun Jun 23 21:11:32 CEST 2024.