c/string/byte/isgraph

Checks if the given character has a graphical representation, i.e. it is either a number, an uppercase letter , a lowercase letter , or a punctuation character, or any graphical character specific to the current C locale.

The behavior is undefined if the value of is not representable as  and is not equal to.

Return value
Non-zero value if the character has a graphical representation character, zero otherwise.