| .\" Copyright (C) 2007 Michael Kerrisk <mtk.manpages@gmail.com> |
| .\" |
| .\" %%%LICENSE_START(VERBATIM) |
| .\" Permission is granted to make and distribute verbatim copies of this |
| .\" manual provided the copyright notice and this permission notice are |
| .\" preserved on all copies. |
| .\" |
| .\" Permission is granted to copy and distribute modified versions of this |
| .\" manual under the conditions for verbatim copying, provided that the |
| .\" entire resulting derived work is distributed under the terms of a |
| .\" permission notice identical to this one. |
| .\" |
| .\" Since the Linux kernel and libraries are constantly changing, this |
| .\" manual page may be incorrect or out-of-date. The author(s) assume no |
| .\" responsibility for errors or omissions, or for damages resulting from |
| .\" the use of the information contained herein. The author(s) may not |
| .\" have taken the same level of care in the production of this manual, |
| .\" which is licensed free of charge, as they might when working |
| .\" professionally. |
| .\" |
| .\" Formatted or processed versions of this manual, if unaccompanied by |
| .\" the source, must acknowledge the copyright and authors of this work. |
| .\" %%%LICENSE_END |
| .\" |
| .\" 2007-10-23 mtk, Nearly a complete rewrite of the earlier page. |
| .TH INTRO 3 2020-11-01 "Linux" "Linux Programmer's Manual" |
| .SH NAME |
| intro \- introduction to library functions |
| .SH 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. |
| .PP |
| Many of the functions described in the section are part of the |
| Standard C Library |
| .RI ( libc ). |
| Some functions are part of other libraries (e.g., |
| the math library, |
| .IR libm , |
| or the real-time library, |
| .IR librt ) |
| in which case the manual page will indicate the linker |
| option needed to link against the required library |
| (e.g., |
| .I \-lm |
| and |
| .IR \-lrt , |
| respectively, |
| for the aforementioned libraries). |
| .PP |
| 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 |
| .I any |
| header files.) |
| In such cases, the required macro is described in the man page. |
| For further information on feature test macros, see |
| .BR feature_test_macros (7). |
| .\" |
| .\" There |
| .\" are various function groups which can be identified by a letter which |
| .\" is appended to the chapter number: |
| .\" .IP (3C) |
| .\" These functions, the functions from chapter 2 and from chapter 3S are |
| .\" contained in the C standard library libc, which will be used by |
| .\" .BR cc (1) |
| .\" by default. |
| .\" .IP (3S) |
| .\" These functions are parts of the |
| .\" .BR stdio (3) |
| .\" library. They are contained in the standard C library libc. |
| .\" .IP (3M) |
| .\" These functions are contained in the arithmetic library libm. They are |
| .\" used by the |
| .\" .BR f77 (1) |
| .\" FORTRAN compiler by default, but not by the |
| .\" .BR cc (1) |
| .\" C compiler, which needs the option \fI\-lm\fP. |
| .\" .IP (3F) |
| .\" These functions are part of the FORTRAN library libF77. There are no |
| .\" special compiler flags needed to use these functions. |
| .\" .IP (3X) |
| .\" Various special libraries. The manual pages documenting their functions |
| .\" specify the library names. |
| .SH CONFORMING TO |
| Certain terms and abbreviations are used to indicate UNIX variants |
| and standards to which calls in this section conform. |
| See |
| .BR standards (7). |
| .SH NOTES |
| .SS 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! |
| .SH SEE ALSO |
| .BR intro (2), |
| .BR errno (3), |
| .BR capabilities (7), |
| .BR credentials (7), |
| .BR environ (7), |
| .BR feature_test_macros (7), |
| .BR libc (7), |
| .BR math_error (7), |
| .BR path_resolution (7), |
| .BR pthreads (7), |
| .BR signal (7), |
| .BR standards (7), |
| .BR system_data_types (7) |