pSOSystem System Calls - Read

pSOS+ System Calls errno_addr
errno_addr Obtains the address of the calling task’s internal errno variable.
#include
unsigned long *errno_addr();
Description
Return Value
Error Codes
Notes
This system call returns the address of the calling task's internal errno variable.
The pSOS+ kernel maintains an internal errno variable for every task. Whenever
an error is detected by any pSOSystem component, the associated error code is
stored into the running task's internal errno variable. The error code can then be
retrieved by referencing the errno macro defined in the header file as
follows:
#define errno (*(errno_addr())
For example, the following statement expands to include a call to errno_addr():
if (errno == ERR_NOMGB)
This system call returns the address of the errno variable of the calling task.
None.
1. errno_addr() provides a unique errno value for each task while maintaining
compatibility with industry standard library semantics. It should never be
necessary to call errno_addr() directly from application code.
2. All pSOSystem components set a task's internal errno variable. However, for
the pSOS+ kernel and pHILE+ file system manager, which return error values
via the function return value, use of the errno macro is superfluous.
3. A successful system call does not clear the previous errno value. errno always
contains the error code from the last unsuccessful call.
pSOSystem System Calls 1-23
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