Returns a double-precision floating point value equal to the number of seconds between successive clock ticks
For C/C++, all of the run-time library routines are actual subroutines. For Fortran, some are actually functions, and some are subroutines. For example:
INTEGER FUNCTION OMP_GET_NUM_THREADS()
Note that for C/C++, you usually need to include the <omp.h> header file.
Fortran routines are not case sensitive, but C/C++ routines are.
For the Lock routines/functions:
The lock variable must be accessed only through the locking routines
For Fortran, the lock variable should be of type integer and of a kind large enough to hold an address.
For C/C++, the lock variable must have type omp_lock_t or type omp_nest_lock_t, depending on the function being used.
Implementations may or may not support all OpenMP API features. For example, if nested parallelism is supported, it may be only nominal, in that a nested parallel region may only have one thread.
Consult your implementation’s documentation for details - or experiment and find out for yourself if you can’t find it in the documentation.
The run-time library routines are discussed in more detail in Appendix A.
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