xref: /illumos-gate/usr/src/test/libc-tests/cfg/symbols/README (revision fc2512cf)

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# This file and its contents are supplied under the terms of the
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# You may only use this file in accordance with the terms of version
# 1.0 of the CDDL.
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# source.  A copy of the CDDL is also available via the Internet at
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#
# Copyright 2015 Garrett D'Amore <garrett@damore.org>
# Copyright 2016 Joyent, Inc.
#

The configuration files in this directory are structured using the
syntax defined in the ../README file.  They make use of the compilation
environments declared in ../compilation.cfg, and are processed by the
symbols test.

We have organized the files by header file, that is the tests for symbols
declared in a header file (e.g. <unistd.h> appear in a file based on that
header file's name (e.g. unistd_h.cfg.)  This is purely for convenience.

Within these various declarations, we have the following field types:

<envs>    This is a list of compilation environments where the symbol
          should be legal.  To indicate that the symbol must not be legal
          an environment group can be prefixed with "-".  For example,
          "SUS+ -SUSv4+" indicates a symbol that is legal in all SUS
	  environments up to SUSv3, and was removed in SUSv4 and subsequent
          versions of SUS.  As you can see, we can list multiple environments
          or environment groups, and we can add or remove to previous groups
          with subsequent ones.

<name>    This is a symbol name.  It follows the rules for C symbol names.

<header>  This is a header file, for example, unistd.h.  Conventionally,
          the header files used should match the file where the test is
          declared.

<type>    This is a C type.  Function types can be declared without their
          names, e.g. "void (*)(int)".  Structures (e.g. "struct stat") and
          pointer types (e.g. "pthead_t *") are legal as well.

Here are the types of declarations in these files:

type | <name> | <header> | <envs>

    Tests for a C type with <name>.  The test verifies that a variable with
    this type can be declared when the <header> is included.

value | <name> | <type> | <header> | <envs>

    Tests for a value named <name>, of type <type>.  The test attempts to
    assign the given value to a scratch variable declared with the given
    type.  The value can be a macro or other C symbol.

define | <name> | <value> | <header> | <envs>

    Tests for a definition named <name>.  The test verifies that the
    pre-processor sees the definition.  If the <value> entry is not
    empty then the check also verifies that there is strict equality
    between the pre-processor value and it.  Only strict equality checks
    are supported at this time.

func | <name> | <type> | <type> [; <type> ]... | <header> | <envs>

    Tests whether a function <name>, returning the first <type>, and
    taking arguments of following <type> values, is declared.  Note that
    the argument types are separated by semicolons.  For varargs style
    functions, leave out the ... part.  For function declarations
    that have no declared arguments, either void can specified, or
    the type list can be omitted.

Examples:

    type | size_t | sys/types.h | ALL
    value | NULL | void * | stdlib.h | ALL
    define | thread_local | | threads.h | -ALL +C11
    define | __alignas_is_defined | 1 | threads.h | -ALL +C11
    func | strnlen | int | const char *; int | string.h | ALL