gpgme_op_createkey errors

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when writing C code using the GPG Made Easy library, the function "gpgme_op_createkey" is always throwing the error "Not supported" and I can't find any solution to resolve this.

1) Does anyone know why this error is being thrown, or what common causes are for this error?
2) Does anyone know of sample C code that can use this function without throwing this error?

When looking through the source code, I noticed that in the "tests" directory there is a file called "run-genkey.c" but when compiled it also throws the same error.

Thank you in advance.
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