How to Print Elements of a C Vector in GDB?

Printing Elements of a C Vector in GDB

When debugging C code in GDB, you may need to examine the contents of a vector. To do so with a vector of integers (std::vector), follow these steps:

Printing the Entire Vector:

print *(myVector._M_impl._M_start)@myVector.size()

This expression accesses the pointer to the internal array of the vector (_M_impl._M_start) and prints the specified number of elements (myVector.size()).

Printing Only the First N Elements:

print *(myVector._M_impl._M_start)@N

Replace N with the number of elements you want to print.

Explanation:

• The pointer to the internal array is stored in _M_impl._M_start.
• The GDB command to print N elements of an array starting at pointer P is: print P@N.
• The total size of the vector can be obtained using myVector.size().

Note: This approach may vary depending on your compiler version. For GCC 4.1.2, this method has been tested to work effectively.

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