fetestexcept(3M)fetestexcept(3M)NAMEfetestexcept() - test floating-point exceptions
The function determines which of a specified subset of the floating-
point exception flags are currently set. The excepts argument speci‐
fies the floating-point exception flags to be queried. The argument
can be constructed as a bitwise OR of the exception macros: and repre‐
sents all the floating-point exceptions.
To use this function, compile either with the default option or with
the and options. Make sure your program includes
For HP Integrity servers, specify on the compiler command line or place
the call to this function under the effect of an affirmative pragma:
If the pragma is placed outside of any top-level declarations in a
file, the pragma will apply to all declarations in the compilation fol‐
lowing the pragma until another pragma is encountered or until the end
of the file is reached.
If the pragma is placed at the beginning of a block (compound state‐
ment), the pragma will apply until another pragma is encountered or
until the end of the block is reached.
For PA-RISC, you might need to use the compiler option in order to pre‐
vent optimizations that can undermine the specified behavior of this
Link in the math library by specifying on the compiler or linker com‐
For more information, see the at the following site:
The function returns the bitwise OR of the exception macros correspond‐
ing to the currently set floating-point exceptions included in excepts.
No errors are defined.
Call if invalid is set, then if overflow is set:
SEE ALSOfeclearexcept(3M), fegetexceptflag(3M), fegettrapenable(3M), feraiseex‐
cept(3M), fesetexceptflag(3M), fesettrapenable(3M), fenv(5).
: ISO/IEC C99 (including Annex F, "IEC 60559 floating-point arith‐