50. POSIX (POS)

These are rules and recommendations for functions that are defined as part of the POSIX family of standards but are not included in ISO/IEC 9899-1999. These rules and recommendations are not part of the core standard because they do not apply in all C language applications and because they represent an incomplete list. The intent of providing these rules is to demonstrate how rules and recommendations for other standards or specific implementations may be integrated with the core C99 recommendations.

Recommendations

POS00-A. Avoid race conditions with multiple threads

POS01-A. Check for the existence of links

Rules

POS30-C. Use the readlink() function properly

POS31-C. Do not unlock or destroy another thread's mutex

POS32-C. Include a mutex when using bit-fields in a multi-threaded environment

POS33-C. Do not use vfork()

POS34-C. Do not call putenv() with a pointer to an automatic variable as the argument

POS35-C. Avoid race conditions while checking for the existence of a symbolic link

Risk Assessment

Recommendation	Severity	Likelihood	Remediation Cost	Priority	Level
POS00-A	2 (medium)	2 (probable)	1 (high)	P4	L3
POS01-A	2 (medium)	3 (likely)	1 (high)	P6	L2
POS02-A	1 (low)	1 (unlikely)	1 (high)	P1	L3

Rule	Severity	Likelihood	Remediation Cost	Priority	Level
POS30-C	1 (low)	2 (probable)	2 (medium)	P4	L3
POS31-C	2 (medium)	2 (probable)	1 (high)	P4	L3
POS32-C	2 (medium)	2 (probable)	2 (medium)	P8	L2
POS33-C	1 (low)	2 (probable)	3 (low)	P6	L2
POS34-C	3 (high)	1 (unlikely)	2 (medium)	P6	L2
POS35-C	3 (high)	3 (likely)	2 (medium)	P18	L1