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Diffstat (limited to 'gcc/fortran/gfortran.texi')
| -rw-r--r-- | gcc/fortran/gfortran.texi | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/gcc/fortran/gfortran.texi b/gcc/fortran/gfortran.texi index a34d82e529d..035dbd74879 100644 --- a/gcc/fortran/gfortran.texi +++ b/gcc/fortran/gfortran.texi @@ -1083,6 +1083,7 @@ might in some way or another become visible to the programmer. @menu * KIND Type Parameters:: * Internal representation of LOGICAL variables:: +* Thread-safety of the runtime library:: @end menu @@ -1157,6 +1158,36 @@ representation of @code{LOGICAL} variables in GNU Fortran is identical to C99 _Bool, except for a possible difference in storage size depending on the kind. + +@node Thread-safety of the runtime library +@section Thread-safety of the runtime library +@cindex thread-safety, threads + +GNU Fortran can be used in programs with multiple threads, e.g. by +using OpenMP, by calling OS thread handling functions via the +@code{ISO_C_BINDING} facility, or by GNU Fortran compiled library code +being called from a multi-threaded program. + +The GNU Fortran runtime library, (@var{libgfortran}), supports being +called concurrently from multiple threads with the following +exceptions. + +During library initialization, the C @code{getenv()} function is used, +which need not be thread-safe. Similarly, the @code{getenv()} +function is used to implement the @code{GET_ENVIRONMENT_VARIABLE} and +@code{GETENV} intrinsics. It is the responsibility of the user to +ensure that the environment is not being updated concurrently when any +of these actions are taking place. + +The @code{EXECUTE_COMMAND_LINE} and @code{SYSTEM} intrinsics are +implemented with the @code{system()} function, which need not be +thread-safe. It is the responsibility of the user to ensure that +@code{system()} is not called concurrently. + +Finally, for platforms not supporting thread-safe @code{POSIX} +functions, further functionality might not be thread-safe. For +details, please consult the documentation for your operating system. + @c --------------------------------------------------------------------- @c Extensions @c --------------------------------------------------------------------- |