How to read the GUID Partition Table (GPT) and its entries?

Question

To read the MBR partition table we use an offset of 0x1be, similarly what is the offset for reading the GP(artition)T(able) entries (ie, number of partitions and their sizes).

I am writing a C program using "gdisk" to create the partitions, I need to write the filesystems onto these partitions. So for this I need to read the GPT header to get the number of partitions and their allocated sizes.

score 3 · Accepted Answer · edited Jun 14 '18 at 16:28

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what is the offset for reading the GPT partition table entries

It typically is located in LBA 2. To verify check offset 0x30 (base-10 offset 48) to the GPT.

edited Jun 14 '18 at 16:28

A Programmer

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answered Jun 28 '15 at 14:13

alk

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Thanks for the quick reply. I get value "2" present at 0x48. i dont know if iam doing the correct thing. Using Sector = 1 offset = 0x48. – swapneel mashalkar Jun 28 '15 at 16:52
`2` means LBA 2. So this should be cylinder 0, head 0, sector 2, offset 0 for the GPT entries. Please see the links in my answer. – alk Jun 28 '15 at 17:01
Sector 2 and offset = 0 works. I need one more clarification. Can we use "gdisk" to create partitions of morethan 2.2TB ? – swapneel mashalkar Jun 28 '15 at 18:03
I need one more clarification. Can we use "gdisk" to create partitions of morethan 2.2TB ? – swapneel mashalkar Jun 28 '15 at 18:07
@swapneelmashalkar: This would suit well as another question. – alk Jun 28 '15 at 18:08
http://stackoverflow.com/questions/31103107/can-we-use-gdisk-to-create-partitions-of-morethan-2-2tb – swapneel mashalkar Jun 28 '15 at 18:12

How to read the GUID Partition Table (GPT) and its entries?

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