ASM generation compiler returned: 0/opt/compiler-explorer/gcc-10.2.0/bin/../lib/gcc/x86_64-linux-gnu/10.2.0/../../../../x86_64-linux-gnu/bin/ld: /lib/x86_64-linux-gnu/crt1.o: in function `_start':(.text+0x24): undefined reference to `main'collect2: error: ld returned 1 exit statusExecution build compiler returned: 1
Thanks for your interest in what Compiler Explorer does with your data. Data protection is really important to the Compiler Explorer team, and we want to be very clear about what we do with your data.
Compiler Explorer was created by and is primarily administrated by Matt Godbolt, along with a number of volunteers (including, but not limited to those listed in our "Authors" documentation). It is run on a best-effort basis, and is not a commercial product. We do our best to keep your data safe, but welcome help from the community: See our GitHub project page if you wish to help.
In order to process compilation and execution requests, your browser sends the source code you typed in the editor window along with your chosen compiler and options to the Compiler Explorer servers. There, the source code is written to disk and your chosen compiler is invoked on it. If your request was to have your code executed, the resulting executable is run. The outputs from compilation and execution are processed and sent back to your web browser, where they're shown. Shortly after this process completes, your source code is deleted from disk. If, in processing your query, an issue with Compiler Explorer is found, your code may be kept for up to a week in order to help debug and diagnose the problem. Only the Compiler Explorer team will have access to your code, and only for the purposes of debugging the site: we will never share your code with anyone.
If you choose a Microsoft compiler, then your code may be sent to and compiled on a machine administrated by Microsoft. Such code is covered by the Microsoft Privacy Policy.
The source code and options are also subject to a one-way hash, which is used to cache the results to speed up subsequent compilations of the same code. The cache is in-memory and on-disk. It's impossible to reconstruct the source code from the hash; but the resulting assembly code or binary output (the compilation result) is stored as plain text. There's no way to enumerate the in-memory cache contents. In exceptional cases, administrator members of the Compiler Explorer team may be able to enumerate the disk caches and retrieve the compilation output, but with no way to trace it back to the source code.
In short: your source code is stored in plaintext for the minimum time feasible to be able to process your request. After that, it is discarded and is inaccessible. In very rare cases your code may be kept for a little longer (at most a week) to help debug issues in Compiler Explorer.
If you choose to share your code using the "Share" dropdown, then the user interface state including the source code is stored. For a "Full" link, this information is encoded into the URL as a URL hash (e.g. https://godbolt.org/#ui_state_and_code). For short URLs, the interface state is stored on Compiler Explorer's servers, and a shortened name uniquely referring to this data is returned. The shortened name comes from a secure hash of the state, and without knowing the name it is infeasible to access the data. Only Compiler Explorer administrators can access this data directly . Obfuscated IP addresses and creation time are stored alongside this data, to enable spam detection. Links of this form look like https://godbolt.org/z/SHORTNAME.
Prior to storing data itself, Compiler Explorer used an external URL shortening service (goo.gl) and the resulting short URL was rewritten as https://godbolt.org/g/SHORTURLPART. The storage for the user experience state in this case remains with the short URL provider, not Compiler Explorer.
Compiler Explorer keeps web logs, which contain semi-anonymised IP addresses, but no other personally identifying information. When a long URL is clicked, the hash part of the URL is not sent to the server, so the user state (including the source code) is NOT exposed in the web log. If a user clicks a short URL, then the short form IS exposed in the web log (as https://godbolt.org/g/SHORTURLPART) and from this the source code can be retrieved. As such, if you create a short URL of your code, your source code and other user state can in principle be retrieved from the web log of Compiler Explorer.
In order to debug and diagnose Compiler Explorer, to help track down and block Denial of Service attacks, and to gather statistics about Compiler Explorer's performance and usage, the web logs are archived. These logs are kept for one month, after which they are permanently deleted.
For certain configurations, we may support executing the results of your compilation on the Compiler Explorer servers. Execution occurs in a heavily locked-down, isolated environment. We have made reasonable efforts to protect both the Compiler Explorer site and other concurrently-processed requests from information leakage due to rogue executions.
Separately, Compiler Explorer uses small pieces of information stored on your computer: Cookies and Browser Local Storage. Cookies are only used with the user's permission, and are used with external analytics services (e.g. Google Analytics) to gather statistics on Compiler Explorer usage. This information is used to help the Compiler Explorer team plan for future updates and hardware upgrades in order to ensure the site remains stable and responsive. Local storage is used to remember user's settings, source code and user interface configuration, so that it's available when the user visits the Compiler Explorer site again. This information is not transmitted to Compiler Explorer, except as described above in order to fulfil the user's requests. There is a separate document covering more on this. Statistics tracking information is kept for 14 months, after which it is removed.
Compiler Explorer is an open source project. If you are concerned about any of the data protection measures outlined above, or about what happens to your source code, you are encouraged to run your own local instance of Compiler Explorer. Instructions on how to do this are on the GitHub project page.
The Compiler Explorer team believes the Compiler Explorer site is compliant with the EU's General Data Protection Regulation (GDPR). Specifically, we store no personally identifying information, we anonymise the little data that we do have and we do not permanently store any user data.
The Controller for the purposes of the General Data Protection Regulation (GDPR), other data protection laws applicable in Member states of the European Union and other provisions related to data protection is:
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