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I know that gdb allows for an already declared variable to be set using the set command.
Is it possible for gdb to dynamically declare a new variable inside the scope of a given function?
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You can create variables in the context of gdb for your convenience, like set $foo = ... and later reference $foo . Obviously such variables are in no way visible to the running code, however. it's not only for inspection. you can change variable values in gdb: stackoverflow.com/questions/3305164/….
The ptype [ARG] command will print the type. Show activity on this post. This question may be related: vtable in polymorphic class of C++ using gdb: (gdb) help set print object Set printing of object's derived type based on vtable info.
The usual way to examine data in your program is with the print command (abbreviated p ), or its synonym inspect . It evaluates and prints the value of an expression of the language your program is written in (see section Using GDB with Different Languages).
You can dynamically allocate some space and use it to store a new variable. Depending on what you mean by "scope of the current function" it may not be what you want.
But here is how it looks like, when you have function func() that takes a pointer to an output parameter:
set $foo = malloc(sizeof(struct funcOutStruct)) call func($foo) p *$foo call free($foo) For C (and probably C++) code, that would be very hard, since doing so in most implementations would involve shifting the stack pointer, which would make the function's exit code fail due to it no longer matching the size of the stack frame. Also all the code in the function that accesses local variables would suddenly risk hitting the wrong location, which is also bad.
So, I don't think so, no.
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