"posix" --- The most common POSIX system calls#

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Este módulo proporciona acceso a la funcionalidad del sistema operativo que está estandarizada por el estándar C y el estándar POSIX (una interfaz Unix finamente disfrazada).

Availability: Unix.

Do not import this module directly. Instead, import the module "os", which provides a portable version of this interface. On Unix, the "os" module provides a superset of the "posix" interface. On non- Unix operating systems the "posix" module is not available, but a subset is always available through the "os" interface. Once "os" is imported, there is no performance penalty in using it instead of "posix". In addition, "os" provides some additional functionality, such as automatically calling "putenv()" when an entry in "os.environ" is changed.

Los errores se notifican como excepciones; las excepciones habituales se proporcionan para los errores de tipo, mientras que los errores notificados por las llamadas del sistema lanzan "OSError".

Soporte de archivos grandes#

Several operating systems (including AIX and Solaris) provide support for files that are larger than 2 GiB from a C programming model where int and long are 32-bit values. This is typically accomplished by defining the relevant size and offset types as 64-bit values. Such files are sometimes referred to as large files.

Large file support is enabled in Python when the size of an "off_t" is larger than a long and the long long is at least as large as an "off_t". It may be necessary to configure and compile Python with certain compiler flags to enable this mode. For example, with Solaris 2.6 and 2.7 you need to do something like:

CFLAGS="getconf LFS_CFLAGS" OPT="-g -O2 $CFLAGS" \ ./configure

En sistemas Linux con capacidad para archivos grandes, esto podría funcionar:

CFLAGS='-D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64' OPT="-g -O2 $CFLAGS" \ ./configure

Contenido notable del módulo#

In addition to many functions described in the "os" module documentation, "posix" defines the following data item:

posix.environ

Diccionario que representa el entorno de cadena en el momento en que se inició el intérprete. Las claves y los valores son bytes en Unix y str en Windows. Por ejemplo, "environ[b'HOME']" ("environ['HOME']" en Windows) es el nombre de ruta de acceso de su directorio principal, equivalente a "getenv("HOME")" en C.

La modificación de este diccionario no afecta al entorno de cadena que transmite "execv()", "popen()" o "system()"; si necesita cambiar el entorno, pase "environ" a "execve()" o agregue asignaciones variables y declaraciones de exportación a la cadena de comandos para "system()" o "popen()".

Distinto en la versión 3.2: En Unix, las claves y los valores son bytes.

Nota:

 The "os" module provides an alternate implementation of "environ"
 which updates the environment on modification. Note also that
 updating "os.environ" will render this dictionary obsolete. Use
 of the "os" module version of this is recommended over direct
 access to the "posix" module.